code: def test_symbolic_output_shape(self):
      from lasagne.layers.base import Layer
  
      class WrongLayer(Layer):
          def get_output_shape_for(self, input_shape):
              return theano.tensor.vector().shape
  
      with pytest.raises(ValueError) as exc:
          WrongLayer((None,)).output_shape
      assert "symbolic output shape" in exc.value.args[0]
  
imports: from mock import Mock
  import numpy
  import pytest
  import theano
label_desc: Use image node_id 16 for calling the TestLayer obj's underlying member method code with example usage: obj.test_symbolic_output_shape() and returns: theano